Various techniques have been developed to locate and map underground utilities and other manmade subsurface structures. Present utility mapping practices take two basic forms: active systems that must have some type of connection to the utility at some accessible point along its path, and passive systems that attempt to map utilities independent of any connection or even prior knowledge of their existence.
Active systems are problematic for various reasons, such as the difficulty and cost of physically accessing the utility and difficulty in sensing non-conductive utilities. Passive systems currently in use often employ GPR. GPR surveys are conducted from the surface, and the location and relative depth to potential utilities are determined from an analysis of reflected energy.
GPR, in general, is a very good sensor for utility mapping purposes, in that GPR is easy to use and provides excellent resolution. However, GPR has problems detecting utilities in certain soil types and conditions that limit GPR's use in many areas of the United States and the world, such as much of southwest United States (e.g., Arizona). Improvements in GPR sensor design can help overcome some aspects of these inherent limitations, but in many geographic areas, GPR should not be solely relied on due to imaging reliability and accuracy concerns.
Before trenching, boring, or otherwise engaging in invasive subsurface activity to install or access utilities, it is imperative to know the location of any existing utilities and/or obstructions in order to assist in trenching or boring operations and minimize safety risks. Currently, utilities that are installed or otherwise discovered during installation may have their corresponding physical locations manually recorded in order to facilitate future installations. One such system is referred to as the One-Call system, where an inquiry call can be made to obtain utility location information from an organization that manually records utility location information, when and if it is provided. However, the One-Call system is not particularly reliable, as only a certain percentage of the utilities are recorded, and those that are recorded may have suspect or imprecise location data. As such, currently-existing location data for buried utilities is incomplete and often questionable in terms of reliability.
There is a need in the utility installation and locating industries to increase the accuracy of buried utility/object detection. There exits a further need to collect, maintain, and disseminate utility location data of increased accuracy. The present invention fulfills these and other needs, and provides additional advantages over the prior art.